PostgreSQL Comparison Operators

Description

Comparison operators, as their name, allows to compare two values. It Compares strings or numbers for relationships such as equality.

List of Comparison Operators

Operators

Description

< ( less than)

Returns true when the left operand is less than the right operand.

> ( greater than)

Returns true when the left operand is greater than the right operand.

<= ( less than or equal )

Returns true when the left operand is less than or equal to the right operand.

>= (greater than or equal)

Returns true when the left operand is greater than or equal to the right operand.

= ( equal )

Returns true when the operands are equal but the type of the operands must be same.

<> or != ( not equal)

Returns true when the operands are not equal.

The sample table

PostgreSQL Less Than ( < ) operator example

If we want to display the list of employees with columns empno, emp_first_name, designame and salary from employee who drawn the salary amount less than 10000, the following SQL can be used.

SQL

SELECT empno,emp_first_name,designame,salary
FROM employee
WHERE salary<10000;

Output

PostgreSQL Greater Than ( > ) operator example

If we want to display the list of employees with columns empno, emp_first_name,designame and salary from employee who drawn the salary amount more than 18000, the following SQL can be used.

SQL

SELECT empno,emp_first_name,designame,salary
FROM employee
WHERE salary>18000;

Output

PostgreSQL Greater Than or Equal( >= ) and Less Than or Equal( <= ) operator example

If we want to display the list of employees with columns empno, emp_first_name, emp_last_name,designame and dt_birth from employee who born between the period 1975-01-01 and 1982-03-31, the following SQL can be used.

SQL

SELECT empno,emp_first_name,emp_last_name,designame,dt_birth
FROM employee
WHERE dt_birth>='1975-01-01'
AND dt_birth<='1982-03-31';

Output

PostgreSQL Equal ( = ) operator example

If we want to display the list of employees with columns empno, emp_first_name, emp_last_name and designation from employee table whose designation is 'CLERCK', the following SQL can be used. .

SQL

SELECT empno,emp_first_name,emp_last_name,designame
FROM employee
WHERE designame='CLERCK';

Output

PostgreSQL Not Equal (<> or != ) operator example

If we want to display the list of employees with columns empno, emp_first_name, emp_last_name and designation from employee table who does not belongs to the designation 'CLERCK' and 'SALESMAN', the following SQL can be used. .

SQL

SELECT empno,emp_first_name,emp_last_name,designame
FROM employee
WHERE designame<>'CLERCK'
AND designame<>'SALESMAN';